June 15, 2017 is the 100th anniversary of the passage of the Espionage Act. Earlier this year, as if to commemorate the centennial, President Trump suggested to then-FBI Director James Comey that he extend the Act into new territory—that he use it to prosecute journalists.

Unfortunately, there is little in the language of the law itself that would limit the application of the Espionage Act’s nondisclosure and possession prohibitions to journalists who did not themselves remove the documents from the control of the government. By their terms, two key sections of the Act seem to threaten criminal liability for journalists who shed light on government secrets. 18 U.S.C. § 793(e), for instance, broadly criminalizes the following:

Whoever having unauthorized possession of, access to, or control over . . . information relating to the national defense, which information the possessor has reason to believe could be used to the injury of the United States or to the advantage of any foreign nation, willfully communicates, delivers, [or]transmits . . . the same to any person not entitled to receive it, or willfully retains the same and fails to deliver it to the officer or employee of the United States entitled to receive it;

A related provision, 18 U.S.C. § 798, reaches anyone “who[] knowingly and willfully communicates . . . or otherwise makes available to an unauthorized person, or publishes, or uses in any manner prejudicial to the safety or interest of the United States” certain classified information.

These provisions have no express exception for journalists reporting on issues of public concern—and no implied shield has emerged from the handful of precedents handed down over the last century. The Supreme Court brushed up against the question for the first and only time in New York Times Co. v. United States, the federal government’s effort to block the publication of the Pentagon Papers. While the court’s brief per curiam opinion didn’t touch the issue, several justices wrote separately to suggest that the Justice Department could still prosecute the reporters responsible for the story after it made the front page.

Why have no such prosecutions followed? In part, probably, because the law is unclear, shot through with undefined terms that courts rarely see an opportunity to interpret. Justice Harlan called the Espionage Act “a singularly opaque statute” in his dissent from New York Times Co.; Professors Harold Edgar and Benno Schmidt, in a 1986 law review article, went so far as to call the statute “incomprehensible if read according to the conventions of legal analysis of text, while paying fair attention to legislative history.” There’s no guarantee that the prosecution of a journalist under the Act would succeed—and from the government’s perspective, a loss would undermine the coercive value of threatening prosecution to protect secret surveillance programs.

There are at least two compelling (but untested) legal arguments that would complicate any effort to prosecute a reporter who relied on leaked documents in that kind of case. In New York Times Co., the lower court thought—and Justice Douglas agreed—that the word “communicates” in § 793(e)’s was never intended to include publication by the media. That question is still an open one. What’s more, at least some Espionage Act precedents suggest that “reason to believe [the leaked information]could be used to the injury of the United States” is a stiff requirement, one that it’s hard to imagine would be satisfied in the case of public reporting. In United States v. Rosen, for instance, the district court for the Eastern District of Virginia insisted that that language “requires the government to demonstrate the likelihood of the defendant’s bad faith purpose to either harm the United States or to aid a foreign government.” In other words, it’s not enough to publish sensitive information that a news organization knows might harm national security; harming U.S. national security needs to be the point of publishing.

The application of the disclosure provisions of the Espionage Act to third party recipients and republishers of government materials is likely unconstitutional under the First Amendment. Bartnicki v. Vopper, a 2001 case in which the Supreme Court afforded near absolute protection to the republication of information pertaining to matters of public interest that the republisher legally acquired even if their source illegally acquired and transmitted it to them. But the interaction of the Bartnicki doctrine and the Espionage Act has never been tested.

In essence, for decades, journalists have been protected against prosecution under the Espionage Act by an informal truce, not a battery of legal arguments. As Justice White noted—disapprovingly—in New York Times Co., a legal carve-out for reporters would “conform[] with the past practice of using the statute only to prosecute those charged with ordinary espionage.” Or as David Pozen described the government’s approach to leak prosecutions in The Leaky Leviathan,“In formal terms this legal regime looks forbidding, draconian. In practical terms, as a frustrated intelligence professional once put it, the system amounts to ‘permissive neglect.’”

That norm may be on the brink of changing. In 2014, Attorney General Eric Holder promised, “As long as I am attorney general, no reporter who is doing his job is going to go to jail.” Attorney General Jeff Sessions declined to make the same basic commitment at his confirmation hearings earlier this year. For better or worse, the Trump Administration may finally test the Espionage Act’s sweeping, ambiguous language against reporters’ core First Amendment rights.

With that test looming and with the 100th birthday of the law upon us, it’s clear that the Espionage Act needs to be reformed. Sign our petition calling for changes to this overly broad and outdated law.